Greenway, the Vikings' most experienced linebacker by three seasons, has embraced a systematic change in the team's defense under new head coach Mike Zimmer while learning the nuances and responsibilities of his new role as the weak-side linebacker.

"This is a first chance for me to learn something completely new," Greenway said after Thursday's OTA practice. "I go through the same growing pains as the younger guys as far as learning the new stuff, sometimes it's even harder for me because I have things so engrained over the years."

Greenway was selected to two Pro Bowls (2011, 2012) while playing under Frazier, who was fired as the team's head coach in December after a tumultuous 2013 season that witnessed a steep decline in the Vikings' defense -- including Greenway as he played through most of the season with a fractured wrist.

The Vikings defense finished at or near the bottom of nearly every statistical category last season: yards per game (31st), points per game (32nd) and third down percentage (30th) as Greenway played alongside a pair of inexperienced linebackers that appeared overmatched by season's end.

For the seven-year veteran, it was a relatively forgetful experience.

"It goes back to stripping yourself down from the tape last year and starting all over again," Greenway said.

Even though Minnesota selected a linebacker with the No. 9 overall pick in this month's draft, that doesn't spell the end for 31-year-old Greenway. Zimmer has noted that rookie Anthony Barr will plug in the team's strong-side linebacker role, previously held by Greenway, while Zimmer vows to do "different things" with Greenway than the previous regime.

On Thursday, Greenway took some snaps from Jasper Brinkley as the first-team defense's middle linebacker. Though Greenway's unsure how the linebacker roles will shake out, Zimmer says it's about versatility.

"When you go into a game with six linebackers, if something happens, they've got to be ready to go," Zimmer said. "So part of the deal with guys is we're trying to give them a lot of different things to do."

Greenway's old tag as the 'Sam' linebacker in Frazier's defense switches to the weak-side (or Will) linebacker under Zimmer - which both coach and player have said equates to nearly the same responsibilities he had for seven seasons under Frazier.

From what we can tell, the Vikings' Sam linebacker (Barr) will serve as the team's primary blitzing back while Greenway fills in a coverage/pursuit role that requires more sideline-to-sideline movement than the Tampa-2 scheme under Frazier, which sent the linebackers backpedaling into zone coverages.

Aside from the similarities, the new terminology, coverage schemes and sub packages provide enough variety for Greenway to stay busy off the field.

"I probably haven't studied this much football in six, seven years," Greenway said. "I'm always carrying that iPad and notebook around, trying to learn and ask as many questions as possible. There's a lot of things to learn and a lot of things these coaches know that come up in this scheme that haven't come up before."